Method of rebottoming metal hull with reinforced concrete



A. A. YEE

Feb. 28, 1967 METHOD OF REBOTTOMING METAL HULL WITH REINFORCED CONCRETE 5 Sheets-Sheet 1 Filed March 16, 1 965 Alfred A. Yee

INVLN TOR.

BY (am Wing 5m A. A. YEE

Feb. 28, 1967 METHOD OF REBOTTOMING METAL HULL WITH REINFORCED CONCRETE 5 Sheets-Sheet 2 Filed March 16, 1965 Alfred A. Yea

INVENTOR.

BY com 5 4W Fm Feb. 28, 1967 A. A. YEE 3,306,245

METHOD OF REBOTTOMING METAL HULL WITH REINFORCED CONCRETE.

Filed March 16, 1965 3 Sheets-Sheet s 3a g0 g5 A ZO Alfred A. Yee

INVENTOR.

WW Em United States Patent Ofiice 3,306,245 Patented Feb.- 28, 1967 3,306,245 METHOD OF REBOTTOMING METAL HULL WITH REINFORCED CONCRETE Alfred A. Yee, 3169 Alika Ave., Honolulu, Hawaii 96817 Filed Mar. 16, 1965, Ser. No. 440,166 3 Claims. (Cl. 114-65) The present invention generally relates to boat hull repair and more particularly relates to a novel method of employing reinforced concrete to repair the bottom and sides of a floating steel vessel.

In present-day metal hull construction and especially in metal or steel barges, it is the usual practice to scrape the bottoms periodically. Such scraping and normal corrosion or rust which is removed by such scraping progressively decrease the thickness of the bottom plates or skin of the vessel. After a number of such scrapings, the metal plates become so thin that a'substantial portion of the bottom and sides of the vessel must be removed and replaced with new plates. Thus, over a period of time, the plates forming the bottom and sides of a barge or similar vessel are progressively replaced. Of course, in order to replace such plates, it is necessary that the vessel be placed in a drydock or otherwise oriented so that the vessel is not floating in Water. This operation is time-consuming and relatively expensive and also requires considerable time during which the vessel is out of service.

In order to eliminate the problems encountered in continually repairing and replacing plates in existing steel hulls, the present invention basically involves the pouring of a thin skin of concrete directly onto the inner surface of the existing bottom and side steel panels of a vessel. The concrete skin is reinforced and anchored to the steel structure by the use of continuous longitudinal steel tendons or tension members such as cables, rods or the like and the longitudinal tendons are transversely space-d throughout the perimeter of the skin. The concrete skin [is further reinforced by continuous transversely extending bar loops which are welded to the steel side and bottom panels at their contact points and layers of cold drawn high tensile wire mesh or rods envelop the continuous steel tendons with one layer of wire mesh being above and one layer of wire mesh being below the steel tendons. The steel tendons reinforce the concrete skin and pass through existing transverse steel frames by the provision of holes or slots formed in the webs of the transverse steel frames. The concrete skin extends throughout the vessel terminating peripherally of the hull above the lightweight draft line both at the bow and stem section and at the port and starboard sides.

By employing the present method, the bottom of the hull will be reinforced and the plates thereof will not have to be replaced. Even if the plates corrode completely through, the reinforced concrete skin will form a bottom for the vessel to enable continued operation thereof over an extended period of time without any necessity of repair or replacement of the steel bottom.

The method of the present invention includes the steps of providing holes or slots in the transverse steel ribs in an existing vessel, stringing longitudinal tendons through such holes or slots, retaining the cables in position by employing transversely extending bar loops, providing a wire mesh above the tendons as well as a wire mesh below the tendons before the tendons are placed through the frames, extending the tendon bar loops up the inner surfaces of the bow and stern portions and the port and starboard sides to a point above the draft line when the vessel is empty and then pouring concrete throughout the inner surface of the hull bottom, up the bow and stern section and up the port and starboard sides to a point above the draft line. The surfaces of the steel frames and reinforcing members in the concrete are coated with an epoxy substance to increase the adherence between the concrete and the reinforcing material.

The method of the present invention is relatively inexpensive to practice and enables prolonged and continued use of the vessel without any loss of substantial service time and the cost of the present method is considerably less than the cost of repair of a metal hull by employing conventional procedures.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings [forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a side elevational view of a floating steel vessel with the rein-forced concrete bottom installed there in with a portion of the hull being broken away illustrating the orientation and extent of the reinforcing bottom;

FIGURE 2 is a top plan view of a portion of a vessel with certain areas thereof broken away to illustrate certain of the structural features of the reinforced concrete bottom;

FIGURE 3 is a detailed sectional view, on an enlarged scale taken substantially upon a plane passing along section line 33 of FIGURE 2 illustrating the orientation of the components of the reinforced concrete bottom in relation to the existing hull structure;

FIGURE 4 is a detailed longitudinal sectional view, on an enlarged scale, illustrating the specific organization of the existing metal hull and transverse ribbing together with the reinforced concrete bottom installed therein;

FIGURE 5 is a detailed sectional view, in an enlarged I scale, taken substantially upon a plane passing along section line 55 of FIGURE 1 illustrating the structural arrangement of the reinforced concrete bottom illustrating the manner in which it extends up the port and starboard sides of the vessel;

FIGURE 6 is a detailed view similar to FIGURE 5 but with only the longitudinal tendons installed through the transverse frame members;

FIGURE 7 is a detailed view illustrating a modified arrangement in which the transverse frames are provided with elongated slot-like openings; and

FIGURE 8 is a detailed sectional view extending longitudinally and illustrating one of the frame members having the structure of FIGURE 7 illustrating the transverse bar loop structure and the manner in which it is attached to the existing bottom and transverse frame member.

Referring now specifically to the drawings, the numeral 10 generally designates a floating vessel such as a metal or steel barge having a steel hull including a bottom plate or plates 12 and port and starboard side walls 14 also of metal. The bow and stern of the barge 10 includes inclined plates or walls 16. The structure of the barge or hull which is in existence is conventional and includes a plurality of transversely extending frame members or ribs 18 of channel-shaped configuration extending laterally of the hull and including vertical webs 20. Also, suitable bulkheads or the like may be provided as indicated at 22 for purposes of the present invention, the existence or non-existence of the bulkhead is immaterial.

The steel bottom 12 and side walls 14 are subject to corrosion, coating and the like and must be periodically scraped which results in progressive reduction in thickness of the metal bottom 12 and metal side walls 14 as well as the inclined bow and stern walls 16. As the thickness of the bottom and walls is reduced, it becomes necessary for safety purposes to replace the metal plates which constitute the bottom and walls of the vessel thus requiring that the vessel be taken out of service and placed in a drydock or the like.

In the present procedure, the existing vessel is, of course, unloaded and cleaned along the inner surface of the bottom and walls and also the surface of the webs 20 and the lower flange of the transverse ribs 18 are also cleaned. Then, each web and bulkheads 22 if they are present, is provided with an aperture or hole 24 therein adjacent to but spaced above the bottom 12 as illustrated specifically in FIGURES 4 and 6. As illustrated in FIGURE 6, the frame members 18 extend up the side walls 14 and are correspondingly provided with holes 24. The holes 24 are spaced apart from each other and longitudinal continuous steel tendons 26 such as cables or flexible rods or the like are inserted through the holes 24 and extend upwardly along the bow section wall and stern section wall to a point above the lightweight draft line. As illustrated, the holes 24 are of a diameter larger than the diameter of the tendons 26 to facilitate the threading of the tendons therethrough.

Extending transversely of the bottom 12 and up the side walls 14 and also extending transversely of the bow and stern walls 16 is a plurality of longitudinally spaced transversely extending bar loops 28 which as illustrated in FIGURE are zig-zag or generally serpentine in configuration. The orientation of the crests of the bar loops 28 is staggered and the tendons 26 are received under the crests as illustrated in FIGURE 5 and as indicated by numeral 30. The low points or crests of the bar loops 28 engages the bottom 12 and also the side walls 14 and the low crests are welded as at 32 to the bottom and side walls as illustrated in FIGURE 5. Where the bar loop extends around the generally sharp corner of the juncture between the bottom and side walls, a modified angulated portion 34 is provided for extending over the tendons 26 to prevent the tendons from moving laterally and also prevenst the tendons from moving vertically upwardly for a purpose described hereinafter.

Orientated in underlying relation to the tendons 26 is a layer of reinforcing mesh wire or mesh rods 36 which may be supported in place by small studs or conventional saddles for supporting reinforcing mesh or the mesh may be supported by the bar loops 28. The layer of wire mesh 36 is supported generally intermediate the position of the longitudinal tendons 26 and the bottom 12 and the wire mesh layer 36 extends up the side walls and the wall of the bow and stem section. A second layer of wire mesh or rods for reinforcing is disposed above the tendons 26 and is designated by numeral 38. This wire mesh may also be supported by suitable studs saddles or may be attached to the transverse bar loops 28 if desired or supported on the top surface thereof. The upper layer of reinforcing wire mesh 38 also extends upwardly of the side walls and bow and stern section of the vessel as illustrated in FIGURE 5.

After the holes are formed, the wire mesh 36 orientated in place, the tendons orientated in place, the transverse bar loops oriented in place and the upper layer of wire mesh orientated properly, the surfaces of the webs 20 as well as the tendons and, if desired, the surfaces of the bar loops and wire mesh are coated with a bonding material such as a conventional epoxy material. Prior to drying of the epoxy material, a skin of concrete 40 is poured directly on the bottom 12 thus encompassing the reinforcing wire mesh, the bar loops 28, the tendons 30 and the reinforcing wire mesh 38 and flows through the enlarged holes 24 to form a monolithic structure with the concrete skin thus being rigidly anchored and fixed to the bottom 12 and reinforced by the various reinforcing elements and rigidly fixed to the transverse ribs 18. The concrete skin is extended up the side walls 14 and also the bow and stern sections 16 and where required, suitable forming may be provided for retaining the concrete in place. The forms are not illustrated in that any conventional form structure may be employed. The epoxy surfaces will securely bond the concrete to the various reinforcing elements and the ribs and also, the inner surface of the bottom 12 may also be provided with the epoxy surfaces as well as the inner surfaces of the side walls, bow and stern sections. Where the concrete skin 40 terminates, the edge surface thereof may be inwardly and downwardly inclined as at 42 to provide for shedding of material from the top edge of the concrete bottom or skin.

As illustrated in FIGURE 4, the reinforcing wire mesh 38 is provided in length slightly greater than the distance between adjacent Webs 20 so that the end portions thereof are turned upwardly slightly at as 44. When the concrete skin 40 is poured, the top surface thereof, of course, is smoothed by a troweling operation and where the concrete skin 40 joins with the web, the person finishing the concrete will form an upwardly curved edge portion 46 to assure that any liquid or other flowable material will not gather adjacent the webs but will be orientated somewhere in the cented portion of the concrete skin between the webs 20. This reduces corrosion of the webs which might occur if water or the like collected at the juncture between the concrete skin and the webs 20 and also eliminates the possibility of such accumulated water seeping between the surface of the webs 20 and the concrete skin.

The concrete skin extends throughout the entire floating vessel and terminates at a point peripherally of the hull above the lightweight draft line.

The tendons 26 are high tensile strength steel and this is also true of the reinforcing wire mesh 36 and the bar loops 28 may be mild steel and the alternate arrangement of the bar loops and the orientation thereof in relation to the tendons prevents the tendons from rising upwardly and being orientated at or above the top surface of the concrete skin when it is poured. The longitudinal tendons are orientated within a concrete skin area and are pulled tautly for purposes of orientation and eliminating kinks but are not tensioned to the extent such that such longitudinal tendons would stress the concrete inasmuch as these tendons as Well as the other reinforcing elements 36 and 38 and the bar loops serve only to reinforce the concrete skin 40. The orientation of the bar loops and the holes through the ribs 18 together with the steel tendons 26 serve to positively secure and lock the concrete skin to the existing vessel structure.

FIGURES 7 and 8 illustrate a modified embodiment of the invention in which components equivalent to those in FIGURES 1-6 are provided with primed reference numerals. In this form of the invention, the vertical webs 20 are provided with elongated slot-like openings 50 with each opening 50 receiving a plurality of laterally spaced longitudinal tendons 26'. As illustrated in FIG- URE 7, the slot-like openings 50 are not continuous but are separated from each other by spaced web portions 52 which are left as is. In other words, when forming the slot-like openings 50, the web 20 is cutaway to form the slot-like openings 50. The web 20' is provided with a transverse bar loop 54 of zig-zag or serpentine configuration as illustrated in FIGURE 7. The bar loop 54 extends alongside of the web 20' and is anchored thereto by welding as at 56. The bottom portion of the bar loop 54 engages and is welded to the bottom 12 as at 58 thus serving to position the longitudinal tendon and also secure the frame web to the bottom. In this form of the invention, the contact areas between the concrete skin and the boat structure may be coated with a bonding agent such as an epoxy material or the like.

While the disclosure of the above invention contemplates the orientation of the reinforced concrete skin on the inner surface of the bottom and lower peripheral wall portion of the hull, it is pointed out that it is also within the purview of this invention to form the reinforced concrete skin on the exterior surface thereof. This may be accomplished by inverting smaller vessels where the concrete skin may be easily troweled in place after the transverse bar loops and wire mesh are orientated in position. If the boat is left upright and placed in a drydock, forms may be placed around the bottom of the hull and the hull supported in spaced relation thereto by any suitable means and then holes cut in the bottom of the hull with the concrete being poured therethrough. Of course, the supporting bar loops and wire mesh are also orientated before the concrete is poured.

It is also within the purview of this invention to employ one or several layers of mesh to reinforce the concrete depending upon the thickness thereof and the requirements of the concrete skin. The concrete skin serves to completely replace the hull plates as the hull plates are worn away or otherwise removed. Also, the wire mesh could be terminated slightly spaced from the web so that the edges thereof are not turned up and this construction would also fall within this invention. As illustrated, the transverse ribs are channel-shaped but in some instances, the ribs are inverted L-shaped members or I-beams or any other suitable structural configurations. In any embodiment of the ribs, the holes or slots are formed therein in a conventional manner. Also, the longitudinal tendons can be prestressed for not only reinforcing the concrete skin but also prestressing the same for increasing the strength characteristics thereof.

The cementitious material may be any of several conventional concrete materials including lightweight concrete or the like and other hardenable substances may be employed having the necessary strength characteristics.

The epoxy bonding material prevents cracking of the concrete skin where it engages the surfaces of the webs and otherwise increases the bonding characteristics between the metallic components and the concrete. Also, other bonding agents may be employed in lieu of epoxy as long as the properties are about the same.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. In a floating vessel having a metal bottom subject to corrosion, a continuous skin of concrete completely covering at least one surface of the bottom and forming a bottom for the vessel in the event of deficiency of any portion of the metal bottom, said concrete skin being reinforced by continuous longitudinal tendons, said metal bottom including a plurality of transverse ribs, each of said ribs having holes receiving said tendons and permitting passage of the concrete for forming a monolithic integrated concrete skin, said tendons being retained in place by transversely extending members of serpentine configuration having spaced bottom edge portions attached to the metal bottom, and upper and lower layers of reinforcing wire mesh embedded in said concrete skin above and below the tendons respectively.

2. The structure as defined in claim 1 wherein said concrete is bonded to said ribs and tendons by an applied coating of bonding agent on the ribs and tendons.

3. In a floating vessel having a metal bottom subject to corrosion, a continuous skin of concrete completely covering the inner surface of the metal bottom and forming a bottom for the vessel in the event of deficiency of any portion of the metal bottom, a plurality of laterally spaced, longitudinally continuous tendons of high tensile strength, means retaining the longitudinal tendons in spaced relation and orientated slightly from the inner surface of the bottom of the vessel, and reinforcing wire mesh disposed above and below the longitudinal tendons for further reinforcing the concrete, said means for retaining the longitudinal tendons including a plurality of transverse bar loops fixed to the metal bottom of the vessel and receiving the longitudinal tendons, said tendons, wire mesh and transverse bar loops being embedded in said concrete skin.

References Cited by the Examiner UNITED STATES PATENTS 133,621 12/1872 Betteley ll469 2,122,300 6/1933 Smith et a1. 114-65 2,389,767 11/1945 Dalton 1l479 2,454,403 11/ 1948 Palmieri 114-65 FOREIGN PATENTS 597,876 2/1948 Great Britain.

MILTON BUCHLER, Primary Examiner.

ANDREW H. FARRELL, FERGUS S. MIDDLETON,

Examiners. 

1. IN A FLOATING VESSEL HAVING A METAL BOTTOM SUBJECT TO CORROSION, A CONTINUOUS SKIN OF CONCRETE COMPLETELY COVERING AT LEAST ONE SURFACE OF THE BOTTOM AND FORMING A BOTTOM FOR THE VESSEL IN THE EVENT OF DEFICIENCY OF ANY PORTION OF THE METAL BOTTOM, SAID CONCRETE SKIN BEING REINFORCED BY CONTINUOUS LONGITUDINAL TENDONS, SAID METAL BOTTOM INCLUDING A PLURALITY OF TRANSVERSE RIBS, EACH OF SAID RIBS HAVING HOLES RECEIVING SAID TENDONS AND PERMITTING PASSAGE OF THE CONCRETE FOR FORMING A MONOLITHIC INTEGRATED CONCRETE SKIN, SAID TENDONS BEING RETAINED IN PLACE BY TRANSVERSELY EXTENDING MEMBERS OF SERPENTINE CONFIGURATION HAVING SPACED BOTTOM EDGE PORTIONS ATTACHED TO THE METAL BOTTOM, AND UPPER AND LOWER LAYERS OF REINFORCING WIRE MESH EMBEDDED IN SAID CONCRETE SKIN ABOVE AND BELOW THE TENDONS RESPECTIVELY. 